The present invention relates generally to motion picture projectors and more particularly to a control arrangement for selectively actuating a rewind mode of operation upon the occurrence of a predetermined film tension condition.
Motion picture projectors normally include a forward and reverse film transporting drive assembly and a controller assembly which is manually movable into various positions for selecting corresponding operating modes. A motion picture projector of this type is described in U.S. Pat. No. 3,952,969 which issued to J. G. Woodier on Apr. 27, 1976.
During the normal forward projection mode and as the end of the film is reached, it is desirable to automatically cease the film transporting action and actuate a rewind mode of operation by sensing the occurrence of a predetermined film tension condition.
While motion picture projectors of the prior art have provided arrangements to cease film transporting and actuate a rewind mode of operation that are generally suitable for their intended purpose, these arrangements are either overly complex, unreliable or are not easily adaptable to the film drive and control mechanisms of projectors currently available. Further, many of the prior arrangements are not disabled during certain operational modes such as still, pause, fast forward and reverse where either high film tension normally occurs or the operator may inadvertently actuate the arrangement.
In accordance with the present invention, it is a principal object to provide an improved arrangement in a projector to automatically cease film transporting when a predetermined film tension condition occurs in predetermined operating modes and actuate a rewind mode of operation.
It is a further object of the present invention to provide a simplified and reliable arrangement to automatically actuate a rewind mode of operation in a projector upon the occurrence of a predetermined film tension condition and wherein the arrangement is conditioned to a sensing mode by the mode controller assembly of the projector and which ceases film transporting action by positioning of the mode controller assembly.
It is another object of the present invention to provide an arrangement to actuate a rewind mode of operation of a projector upon the occurrence of a predetermined film tension condition that includes a locking arrangement to inhibit operation in certain predetermined operational modes.
It is a still further object of the present invention to provide an automatic rewind arrangement in a projector that positions a mode controller assembly to a position where film transporting is deactuated and directly effects conditiong of a film transporting drive assembly of the projector.
It is yet another object of the present invention to provide an automatic rewind arrangement in a projector when a high tension film condition is detected that is easily adaptable to projector apparatus and avoids one or more of the above-described disadvantages of the prior art arrangements.
These and other objects of the present invention are efficiently achieved by providing a control arrangement to selectively actuate a rewind mode of operation upon the occurrence of a predetermined film tension condition in a projector provided with a forward and reverse film transporting drive assembly, an assembly for sensing a predetermined film tension condition and a manually moveable mode controller assembly for selecting various operational modes.
The selectively actuated rewind control arrangement includes a controller assembly conditioner mechanism that is responsive to the tension sensing assembly and effective to position the controller assembly from a first predetermined projector operating mode such as a normal forward mode to a second predetermined operating mode such as a still mode when the predetermined film tension condition is sensed. A rewind mode actuator mechanism responsive to the controller assembly conditioner mechanism is provided to control the film transporting drive assembly in the rewind mode upon the operation of the controller assembly conditioner mechanism.
The rewind mode actuator mechanism in one arrangement includes a translating member for converting a linear displacement of the controller assembly conditioning mechanism to a rotational movement which is connected to rotate a coupling rod member carrying a displacing actuator member. The displacing actuator member is arranged to displace a reverse drive assembly member actuator in the film transporting assembly to condition the film transporting assembly in a rewind mode.
In a second arrangement, a pivotable link converts the linear displacement of the controller assembly conditioning mechanism to a vertical displacement of a connecting rod that is coupled through a connecting pivot plate to pivot a reverse drive actuator member to displace the reverse drive assembly actuator.
The rewind mode actuator is also provided with actuator members to deactuate a gate and side tension mechanism of the projector in the rewind modes and to deactuate a shuttle mechanism.